Collar for drill steels



APril 1958 c. E. SEARS 2,830,792

COLLAR FOR DRILL STEELS Filed Oct. 13, 1954 'a g. V 4

L BY/III/II/l "(I/Ill Ill/l Il/JL/ INVENTOR FIG-4 CLARENCE E. SEARSFla-2 BY ms ATTORNEY United States Patents COLLAR FOR DRILL STEELSClarence E. Sears, Sherbrooke, Quebec, Canada, assignor toIngersoll-Rand Company, New York, N. Y., a corporation of New JerseyApplication October 13, 1954, Serial No. 462,077

7 Claims. (Cl. 255-37) This invention relates to drill steels, and moreparticularly to a collar that is readily attachable to the shank portionof a drill steel.

Drill steels of the type to which the present invention pertains areused in percussive rock drills equipped with retainers for cooperationwith the collar to maintain within workable limits the shank lengthrecommended by the manufacturers as well as to retain the shank end ofthe drill steel in the rock drill and to interlockingly engage thecollar for withdrawing the drill steel from a drill hole. i

Heretofore, it has been customary to form the collar by upsetting aportion of the steel at a point chosen as the juncture of the bodyportion of the steel and its shank. This mode of forming the collarrequires repeated heating and forging operations, and in the case ofhollow drill steels it becomes necessary to pin-out the material thatflows into the passage in the drill steel after each forging operation.

These operations, as will be readily appreciated, require a considerabledegree of skill and numerous and costly mechanisms for carrying themout, and in many instances defects develop in the area of the collarthat cause failure of the drill steel when subjected to the heavystresses of drilling. i

It is accordingly an object of this invention to obviate the need ofdisturbing the initial form of a drill steel requiring a collar.

Another object is, to enable a drill steel to be expeditiously equippedwith a collar without the need of special skill or costly machinery.

Other objects will be in part obvious and in part pointed outhereinafter.

In the drawings accompanying this specification and in which similarreference numerals refer to similar parts,

Figure l is a side elevation of the front end portion of a rock drilland a drill steel having its shank end extending into the rock drill,the drill steel being equipped with a collar constructed in accordancewith the practice of the invention,

Fig. 2 is an elevation, partly in section, of a drill steel and a collarafiixed thereto,

Fig. 3 is a transverse view through Fig. 2 on the line 3-3,

Fig. 4 is a fragmentary portion of the casing parts of the collarshowing them in position for attachment to each other,

5 is a view similar to Fig.4 showing the casing parts permanentlysecured together, i

Fig. 6 is an elevation, partly in section, of the shank portion of adrill steel, a collar and a pilot seated upon the end of the drill steelfor guiding the collar onto the drill steel, and

Fig. 7 is a transverse view taken through Fig. 6 on the line 7-7.

Referring to the drawings and at first more particular- Patented Apr.15, 1958 1y to Figure 1, 20 designates the front end portion of a rockdrill, 21 a drill steel actuated by the hammer piston 22 of the rockdrill and 23 a retainer for preventing ejection of the drill steel fromthe rock drill. The casing of the rock drill 20 is provided, as iscustomary, with trunnions 24 to support the retainer 23, and the yoke 25of the retainer partly encircles the drill steel 21 at a point forwardlyof the collar 26.

The collar 26 comprises an elongated member 27 in the form of a sleevethat may be shaped internally to conform to the contour of the drillsteel 21 or may, if desired, be of cylindrical shape to receive drillsteels of corresponding or polygonal shapes. The member is constructedof elastic material, as for example rubber or neoprene which is readilydeformable and may, therefore, be conveniently constricted and pressedinto firm gripping engagement with the drill steel.

In a preferred form, the member 27 is exteriorly of cylindrical shapeand its bore 23 comprises a similarly shaped intermediate portion 29 ofsmaller diameter than the drill steel. The front and rear end portions30 and 31 of the bore 28 flare outwardly toward the ends of the memberto accommodate the material that is displaced at the intermediateportion of the member during the operation of attaching the collar tothe drill steel.

The member 27 is encased'in a sleeve 32 to which its peripheral surface33 is bonded and is of somewhat less length than the sleeve. The frontend 34 of the member 27 initially lies flush with the corresponding endof the sleeve and some of the material of the member 27 will thenprotrude from the sleeve when attached to the drill steel 21, asindicated at 35 in Figs. 1 and 2 of the drawings, to cushion the blow ofthe collar against the yoke 25, Owing to the difference in lengthsbetween the sleeve 32 and the member 27 a space 36 will remain in therearward end of the sleeve into which the material of the memberdisplaced by the drill steel may flow. The space 36 is, however, ofsufficient length to preclude the complete filling of the space 36 inorder to avoid contact of the rearward end of the member 27 with a cap37 on the adjacent end of the sleeve and thereby enable the member toyield slightly when the collar assembly is thrust against the rock drillor the retainer. The cap 37 serves as a buffer for the sleeve to protectit against damage upon impact of the colar against the front end of therock drill, as when the drill steel rebounds from the working surface.

The cap 37 has an aperture 38 therethrough to slidably receive the drillsteel, and in the forward surface of the cap is an annular groove 39 thesides 40 of which diverge from the open end of the groove. The bottom ofthe groove consists of a pair of inclined surfaces 41 that define anannular edge 42 at the line of convergence to engage the end of thesleeve and swage the adjacent portion thereof into firm engagement withthe side surfaces 46 of the groove. Such flaring of the sleeve withinthe groove may be readily effected by the force of the impact of thesleeve against the edge 42 when the collar assembly I is thrust againstthe rock drill by the drill steel.

Whenever it is intended to attach a collar to a drill steel, theassembly comprising the member 27, the sleeve 32 and with the cap 37loosely seated upon the sleeve are disposed upon a pilot 43 of coneshape seated upon the rearward end of the drill steel. Pressure of asuitable value is then applied to the cap 37 and the assembly is forcedthereby along the pilot which will gradually displace the material ofthe member 27. When the member 27 passes over the large end of the pilotit will be interiorly of the correct size and shape to receive the drillsteel and the collar may then be slid along the length thereof to thedesired location.

In actual practice, it has been found that the collar will remain in thecorrect assembled position throughout the life of the drill steel,irrespective of any jars or shocks it may re'eeive in service and 'that,although pressed inrm'ovably" against the steel by the sleeve 32, themember 27 retains sulfici'en't resiliency to-adequately cushion theblows of the sleeve against the rock drilland the retainer 23 andthereby minimize damage to the collar assembly.

T claim:

l. The combination with a drill steel, of a collar including an elasticmember to encircle the drill steel, a sleeve to encircle and constrictthe elastic memberinto firm grippinge'ngagement with the drill steel,and a cap on one end of the sleeve having a sliding fit on the drillsteel and having its inner side surface spaced from the adjacent end ofsaid member.

2'. The combination with a' drill steel, of a. collar including anelastic member to encirclethe drill steel, a sleeve to encircle andconstrict the elastic member into firm gripping engagement with thedrill steel and being bo'nrledto the peripheral surface of the elasticmember and being positioned on said member such that one end portion ofthe sleeve extends beyond the associated end of said member, and a capon said end of the sleeve and having a slidingfi t on the drill steel.

3. The combination with a drill steel, of a collar including an elasticmember to encircle the drill steel and having a smaller internaldiameter when unstressed than the diameter of the drill steel, a sleeveto encircle and constrict the elastic member into firm grippingengagement with the drill steel and being bonded to the peripheralsurface of the elastic member, the unstressed outside dimensions of saidmember correponding substantially to the internal dimensions of saidsleeve, and a cap on one end of the sleeve having a sliding fit on thedrill steel.

4. The combination with a drill steel, of a collar including an elasticmember to encircle the drill steel, a sleeve of greater length than theunstressed length of the elastic member to encircle and constrict saidmember into firm gripping engagement with the drill steel and having oneend initially flush with an end of the elastic member, said sleeve beingbonded to the elastic member, and a separate cap mounted on the otherend of the sleeve having a sliding fit on the drill steel.

5". The'combination with a drill steel, of an elastic member to encirclethe drill steel and having a smaller internal diameter than the diameterof the drill steel, a sleeve to encircle and constrict the elasticmember into firm gripping engagement with the drill steel and beingbonded to the elastic member, a cap having a sliding fit on the drillsteel and having an annular groove of dovetail cross-sectionin one sidethereof, and a flared end on the sleeve lying Within the groove tosecure the cap to the sleeve.

6. The combination with a drill steel, of an elastic member to encirclea drill steel, a sleeve to encircle and constrict the elastic memberinto firm gripping engagement with the drill steel, a capfor the sleeveencircling the drill steel and having an annular groove in one side toreceive an end portion of the sleeve, and means at the bottom of thegroove to swage such end portion of the sleeve into firm engagement withthe sides of the groove accordingly as the end portion of the sleeve isdriven into the groove.

7. The combination with a drill steel, of an elastic member to encirclea drill steel, a sleeve to encircle and constrict the elastic memberinto firm gripping engagement with the drill steel, a cap for the sleeveencircling the drill steel and having an annular groove of dove-tailcross-section in one side to receive an end portion of the sleeve, and aWedge-shaped bottom in the groove to swage such end portion into firmengagement with the sides of the groove accordingly as said end portionis driven into the groove.

References Cited in the file of this patent UNITED STATES PATENTSGreat'Britain Mar. 31, 1943

